1. Field of the Invention
The present invention is related to a method of performing network personalization on a mobile device, and more particularly, to a method of performing network personalization on a mobile device in order to distinguish smartcards issued by different service providers.
2. Description of the Prior Art
Subscriber identity module (SIM) card is a smartcard that securely stores the international mobile subscriber identity (IMSI) used to identify and authenticate subscribers, short message service (SMS) data and contact information on mobile telephony devices. The hardware structure of a SIM card includes a central process unit (CPU), read-only memory (ROM), random access memory (RAM), electrically erasable programmable read-only memory (EEPROM), and an input/output (I/O) circuit. The hierarchical logic data structure of a SIM card includes 3 types of files: elementary file (EF), dedicated file (DF) and master file (MF).
According to the 3rd Generation Partnership Project (3GPP) specification TS 22.022, there are five features to personalize user equipment (UE): network personalization, network subset personalization, service provider (SP) personalization, corporate personalization, and SIM/USIM personalization. During the booting process, the UE obtains the IMSI from its SIM card, and passes this to the mobile operator requesting access and authentication. If the SIM card is locked, the user may have to pass a valid personal identification number (PIN) before the SIM card reveals this information.
In the prior art method of performing network personalization on a mobile device, the mobile country code (MCC) and the mobile network code (MNC) of a specific network are used as feature data. During the booting process, the mobile device is configured to read the contents of the international mobile subscriber identity elementary file (EFIMSI) from the currently inserted SIM/USIM card. If the corresponding MCC and MNC indicated in the international mobile subscriber identity elementary file EFIMSI matches the previously stored feature data, the mobile device may operate in a normal mode; if there is no match, the mobile can only operate in a restricted mode. In other words, a specific mobile device which has been network personalized can only operate in the normal mode when inserted with the SIM card issued by a specific service provider.
FIG. 1 is a diagram illustrating the international mobile subscriber identity elementary file EFIMSI of SIM/USIM cards defined in the 3GPP specification TS 51.011. as depicted in field 10, bytes 2˜9 are used to stored IMSI data. According to the 3GPP specification TS 23.003, IMSI data includes a 3-digit MCC for identifying uniquely the country of domicile of the service provider and a 2-digit or 3-digit MNC for identifying the home (public land mobile network, PLMN) of the service provider.
If a service provider A and a service provider B are cooperative operators, the SIM cards issued by both service providers contain the international mobile subscriber identity elementary file EFIMSI which indicate identical MCC and MNC. Therefore, the prior art method of performing network personalization is unable to distinguish the SIM card issued by the service provider A and the SIM card issued by the service provider B.